Computer system



Feb. 28, 1961 s. B. TOBEY COMPUTER SYSTEM Filed April 9, 1958 I N v/v713/? 5. 5'. 7"UEE 5 T TURNEH turning the dial an amount equal to B K KUnited States Patent COMPUTER SYSTEM Silas B. Tobey, Westfield, N.J.,assignor to Western Electric Company, Incorporated, New York, N.Y., acorporation of New York Filed Apr. 9, 1958, Ser NO. 727,435 3 Claims.(Cl. 324-60) mining the distributed capacitance of an inductor involvesresonating the inductor at two different frequencies, by adding externalcapacitance across the inductor, and then substituting the externalresonating capacitance values in a mathematical equation involving atleast two different mathematical computations relating each of thecapacitance values with the resonating frequencies.

' An object of the invention is a computer for accumulating the resultsof a series of different mathematical "computations.

Another object is a system for automatically solving equations of thetype mentioned above.

Still another object is to determine directly the distributedcapacitance of inductors.

A computer system incorporating the general features of the inventionutilizes a mechanical arrangement wherein a rotatable element is drivenan amount proportional to the displacement in a variable data inputdevice and the element in turn drives a calibrated output dial throughselectively actuated transmission trains for rotating a common outputmember for driving the dial. Different mathematical functions areperformed by each of the transmission trains on data represented by thepositioning of the variable device so that by successively operating thetrains for different data positions of the variable device, the resultsof a number of mathematical operations maybe accumulated and indicateddirectly bythe dial.

.As applied to solving an equation of the form:

where B and B correspond to two positions of the variable device and K Kand K are constants, one of two transmission trains rotates the outputmember the constant K times that of the element; the other train rotatesthe ouput gear the constant K times that of the element and the outputmember drives the dial an amount equal to the constant K times its ownrotation. Starting from a zero .or reference position of both thevariable device and the dial, the first train is rendered operative andthe variable device is moved to position B thereby driving the dial to aposition indicating B K K Both trains are then disabled and the variabledevice is returned to the reference position and then the second trainis rendered operative and the variable device is moved to position B Thefinal dial setting then is the solution of the Equation 1 above.

In a preferred embodiment of the invention, as applied to themeasurement of distributed capacitance of high Q inductors, a linearlyvariable standard capacitor "ice in a conventional alternating currentcapacitance bridge is directly coupled to the rotatable element. Theinductor to be tested is connected into the bridge which is normallybalanced and the bridge is rebalanced at a first frequency f byadjusting the capacitor to null the bridge while a first of twotransmission trains is rendered'operative. Both transmission trains arethen rendered inoperative and the adjustable capacitance is returned toits normal balance position. Following this the second transmissiontrain is rendered operative and the bridge is rebalanced at the secondfrequency f At the completion of this operation the dial isautomatically positioned to indicate the desired distributed capacitancedirectly.

These and other features of the invention will be more fully understoodfrom the following detailed description when taken in conjunction withthe accompanying drawing, in which:

The single figure of the drawing discloses a schematic diagram of asystem forautom'atically computing distributed capacitance of a high Qinductor.

The equation for distributed capacitance of high Q inductors, which iswell known in the art, is as follows:

K C, 02 T where C is the symbol for distributed capacitance; K is aconstant equal to and K is a constant equal to This Equation 2 is of theform of Equation 1 above where and the sign of the second factor isnegative.

The system disclosed in the drawing utilizes a conventional capacitancebridge 1, having test terminals 3 and 4 connected to opposing electrodesof a linearly variable capacitor 7. Movable electrode 8 of the capacitoris connected by means of shaft 9 to a rotatable element or gear 10 whichis rotatable with the electrode 8. The bridge is energized from a source2 and has a detector 6 for indicating a bridge balance or null.

The rotatable element 10 is part of two different gear trains forrotating an output gear 11 which, in turn, drives a calibrated dial 12.The gear ratio between the output gear 11 and the dial is equal to 1:KThe first gear train includes the gears 10, 14 and 11 with a disablingclutch 15 connected between gear 14 and the output gear 11. The secondgear train comprises the gears 10, 16, 17 and 11 with a disabling clutch18 connected between gears 16 and 17. The gear ratio between element 10and gear 14 is equal to 1.:K while that between element 16 and gear 16is equal to 1:K which, in the case disclosed for solving the Equation 2,is equal to 1: 1. The gear ratio between gears 17 and 11 is 1:1, thegear 17 serving to reverse the direction of rotation of the output gear11 when the second gear train is operative and thereby changes the signof the factor resulting from the operation of this gear train, asrequired for Equation 2 above. The clutches 15 and 18 are energized froma direct current source 19 and a switch 29 in series therewith isprovided for disabling both clutches to permit setting the dial 12independently of the element 10 or the bridge capacitor 7. A switch 20is also included in the clutch circuit for selectively energizing theclutches as required. In one position of the switch 20, one of the 3clutches is energized and the other clutch is tie-energized, and viceversa for the other position.

In making a measurement of the distributed capacitance of an inductor 5connected to the bridge test terminals 3 and 4, the dial 12 is initiallyset to a reference or starting zero" position, as indicated in thedrawing, and the capacitor 7 is simultaneously set to a referencesetting C For this operation, both clutches are disabled by openingswitch 29 in thecommon energizing lead from the source 19. 'The Ccapacitance value for capacitor 7 is the capacitance required to balancethe bridge when the test terminals are open. The bridge is thenenergized and clutch 15 actuated by the switch 24!, that is, with theswitch 20' in the position shown in the drawing, and clutch 18 isde-energized and rendered inoperative. The alternating current source2is adjusted to apply a signal at the frequency f to the bridge, and theelectrode 8 of the. capacitor 7 is rotated to produce a null in thedetector 6 indicating that the inductor is resonated and presentssubstantially infinite impedance across the electrodes of capacitor 7.This operation changes the capacitance of capacitor 7 by a value of Cthe capacitance required to resonate the inductor at the frequency fSince clutch 15 is energized for this operation, the first gear train It14 and 11 causes the output dial to be turned to a position so that theindicator 28 is aligned with the dial 12 at a value K C K The followingoperations are then performed in succession: switch 29 is opened andcapacitor 7 is reset to the value C switch 29 is reclosed; the output ofthe bridge source is changed'to the second frequency f and switch 20 isactuated so that clutch 18 is energized and clutch 15 is de-energized;and the rotatable electrode 8 of the capacitor 7 is again adjusted toproduce a bridge balance thereby driving the second gear train 10, 16,17 and 11 to rotate the output dial 12 an amount equal to 'C K K Thechange from C in the capacitance of capacitor 7 then is the capacitancerequired to resonate the inductor 5 at the frequency f Thefinal'indication on the dial is equal to the first indication asproduced with the first'bridge balance less an amount corresponding tothe second balance so that C of Equation 2 will be indicated directly bythe indicator 28,

g In the event the sign or of either factor of Equation 1 or 2 must bereversed, for example, be made different from that disclosed in thepresent system of the drawing, an idler gear may be interposed betweenelement and either gear 14 or 16, as required to reverse the directionof rotation of the output gear 11 thereby. In the system shown in thedrawing, since it is desired to subtract the second factor C K K fromthe first (C K K the second gear train 10, 16, 17 and 11 is designed torotate the output gear 11 in a direction opposite that resulting fromthe operation of the first gear train 10, 14 and 11.

' It is to be understood that the above described arrangements aresimply illustrative of the application of the principles of invention.Numerous other arrangements may be readily devised by those skilled inthe art which will embody the principles of the invention and fallwithin the spirit and scope thereof.

What is claimed is:

1. A system for determining the distributed capacitance of electricalcomponents comprising an alternating current bridge having a linearlyvariable nulling capacitor, means for connecting a component to betested in parallel with the capacitor, a rotatable element, means forrotating the element an amount proportional to a displacement in theadjustable capacitor, an output dial having calibrations thereon andindicating means for the dial, a rotatable output member for.,rotatingthe dial a constant K times its own rotation, a first transmission trainfor rotating the output member a constant K times the rotation of therotatable element, a second transmission train for rotating the outputmember a consant K times the rotation of the rotatable element, andmeans for selectively rendering the transmission trains operable.

2. A system for determining the distributed'capacitance of high Qinductors by solving the equation 'C C K K C K where C equals thedistributed capacitance; C and, C are the values of capacitance requiredto resonate an inductor under test at frequencies 7' and f respectively,and K and K are constants corresponding to the frequencies f and frespectively, said system comprising an alternating current capacitancebridge with a linearly variablenulling capacitor, means for connecting acomponent to be tested in parallel with the capacitor, rotary means foradjusting the capacitor, an energizing source for the bridge operable atfrequencies f and f a rotatable element, a shaft connecting the .elementwith said rotary means for rotating the element synchronously with therotary means, an output dial having calibrations thereon and indicatingmeans for the dial, an output gear for rotating the dial a constant Ktimes its own rotation, a first gear train for rotating the output geara constant K times the rotation of the rotary f and f respectively, andK and K are constants corresponding to the frequencies f and frespectively, said system comprising an alternating current capacitancebridge with a linearly variable nulling capacitor, means for connectinga component to be tested in another branch, rotary means for adjustingthe capacitor, a rotatable element, a shaft connecting the element withthe rotary means for rotating the element synchronously with the rotarymeans, an output dial having calibrations thereon and indicating meansfor the dial, an output gear for rotating the dial a constant K timesits own rotation, a first gear train for rotating the output gear aconstant K times and in the opposite direction of the rotation of therotatable element, a second gear train for rotating the output gear anamount equal to and in the same direction as the rotatable element, aclutch in each of the gear trains, means for selectively actuating oneand de-actuating the other of the clutches, and means for simultaneouslydisabling both clutches.

References Cited in the file of this patent UNITED STATES PATENTS1,653,462 Jenny Dec. 20, 1927 2,380,846 Josepho July 31, 1945 2,468,334Kennedy Apr. 26, 1949 2,607,828 Razek Aug. 19, 1952 2,716,520 Kellogg etal. Aug. 30, 1955

